Chemical and physical variability in the as-received state of aluminium oxide
and aluminium nitride ceramic substrate materials used in optoelectronic
modules currently leads to a process yield less than 100% when adhesives
are used for assembly and interconnection. The phenomenon of epoxy bleed
is a contributing factor to this yield and steps are not yet taken in the industry
to control or inhibit the undesirable wetting.
Standard surface texture measurement techniques, XPS and contact angle
measurements were implemented to characterise and compare commercial
as-received samples. The quality controls currently in place are assessed and
additional analysis methods in the QC stage are suggested for increasing
yield. Commercially available conductive and thermally conductive adhesives,
also used in optoelectronic module manufacture, were studied along with the
surfaces.